Satyanarayana and J. Amarnath and A. Manickavasagam and KVV. Paper P, authored by Vinay S. Prabhavalkar and Vijay R. Uday reddy and G. Jithendra Naidu and S. Paper P, authored by N. Krishna Kumari and G. Tulasi Ram Das and M. These predictions are derived from a mathematical model of the motor that depends on the motor These predictions are derived from a mathematical model of the motor that depends on the motor parameters.
But, these parameters may not match with their actual values. These parametric uncertainties lead to inaccurate predictions of torque and stator flux and affect the performance of the predictive algorithm. This paper presents a modified predictive torque control for a permanent magnet synchronous motor PMSM to reduce the torque ripple at the presence of parametric uncertainty by improving the prediction accurateness. Simulation and experimental results are provided to show the effect of the proposed method.
Design of matrix converter in windmill for frequency stabilisation. The wind energy is considered to be one of the poor quality energies due to the variation of the velocity and direction of the wind. These variations cause fluctuations in the input power and the frequency, thereby affecting the operation These variations cause fluctuations in the input power and the frequency, thereby affecting the operation of the system.
At a given wind velocity, the mechanical power available from a wind turbine is a function of its shaft speed. The shaft speed is varying due to the variations in the wind velocity; thereby a varying frequency and varying voltage is developed at the output of the induction generator.
The battery is replaced by a grid-connected converter. Table 1 shows the key parameters of system. Figure 16 shows the converter waveforms in different conditions.
The DC bus voltage and grid-connected current are shown in Figure 16 a when the converter output with full load in charging. Fourier analysis is made for ; the THD of current is 1. The step response waveforms are shown in Figure 16 b. The system performs well in step response and full load with designed control schemes and parameters. And the phase current THD is 2. Before the power flow changes, the DC-bus voltage is V. From Figure 16 d , in charging, and are at the same frequency and phase.
On the contrary, in discharging, the current and voltage are at the same frequency but opposite phase. As a result, the converter is stable and works well in the power flow reverse condition. The experiment results presented here further demonstrate the effectiveness of the converter proposed in this paper. As shown in Figure 17 a , the lowest efficiency is Figure 17 b gives the converter power factor curve in charge state and discharge state.
In charging, the lowest and highest power factors are 0. In discharging, the lowest and highest power factors are 0. Form Figure 17 b , it can be shown that the converter has a unit power factor. Figure 17 c shows the THD of the converter. And the lowest THD is 1. Therefore, the converter grid-connected current is low THD. But, under other power condition, the converter works well.
And the PI controllers of voltage and current closed loop for the converter are designed. Simulation and experiment results show that the converter works well for V2G application with unity power factor, low voltage ripple, high efficiency, and low current THD. The data used to support the findings of this study are available from the corresponding author upon request. The authors declare that they have no conflicts of interest regarding the publication of this paper.
This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Article of the Year Award: Outstanding research contributions of , as selected by our Chief Editors. Read the winning articles. Journal overview.
Special Issues. Academic Editor: Mohamedy Hamdy. Received 01 Jul Revised 14 Aug Accepted 25 Aug Published 07 Sep Abstract The smart grid and electric vehicles EVs are widely used all over the world.
Introduction Recently, with the environmental degradation, climate change, and the shortage of fossil energy, the traditional energy costs have risen a lot. System Configuration and Model 2. System Configuration The configuration of V2G system is shown in Figure 1 ; the system consists of three parts, AC grid, converters, and loads. Figure 1. Figure 2. Figure 3. The model of three-phase converter in synchronous frame. Figure 4. Figure 5. Figure 6. Current loop control diagram of grid voltage feedforward decoupling.
Figure 7. Figure 8. Figure 9. Figure Table 1. The Bode diagram of system. Step response of converter.
The waveforms of V2G system in different conditions. The curve of converter under different load conditions. References S. Habib, M. Khan, F. Abbas, L. Sang, M. In this type of inverter, one or two series inductors are used between one or both limbs of the connection between the rectifier and inverter.
The rectifier used here is a phase-controlled switching device like Thyristor Bridge. In this type of converter, the DC link consists of a shunt capacitor and the rectifier consists of a diode bridge. The diode bridges are preferred for the low load as the AC line distortion and low power factor caused by the Diode Bridge are lesser than the Thyristor Bridge.
However, the AC to AC converters with a DC link is not recommended for high-power ratings as the DC link passive component required capacity increases with the increase in power rating. Matrix converters are used for converting AC to AC directly without using any DC link for increasing the reliability and efficiency of the system by reducing the cost and losses of the DC-link storage element.
Matrix converters are again classified into different types based on the number of components used. The function of a sparse matrix converter is identical to the direct matrix converter, but here the number of switches required is less than the direct matrix converter, and thus the reliability of the system can be improved by reducing the controlling complexity.
The number of diodes is increased with the reduced number of transistors compared to the sparse matrix converter, and thus, due to more number of diodes, the conduction losses are high. These are used for variable speed drives of low dynamics as the input stage of this converter is unidirectional, and due to this, there is an admissible phase displacement between the input current fundamental and input voltage.
These are again classified into two types based on the number of stages they take for conversion, if the voltage and current both are converted in a single stage, then that converter can be called as a Hybrid Direct Matrix Converter. If the voltage and current are converted in two different stages, then that converter can be called a Hybrid Indirect Matrix Converter. The reference system xyz was defined by the following convention: x is parallel to a , y is perpendicular to a and z is parallel to c and perpendicular to the xy plane.
In the used notation, a and c denote the crystallographic axes of the hexagonal system. Structure of BTBO crystal a a view along the c axis b structure projection according to the xyz orientation [ 27 ]. In particular, Fig. In Fig. Moreover, we have already presented the detailed description of BTBO structure in our previous paper [ 13 ].
The unit cell parameters of each synthesized sample are presented in Table 1. All the materials discussed had different irregular microstructures Fig. The large grains are often agglomerations of much smaller ones, of up to a micrometer in size. However, large portions of the large grains are monolithic. The only significant difference is that the sizes of the largest agglomerates reach 30 microns. Compared to previous ones, there are no such large agglomerates made of small grains, and the largest observed grains are monolithic.
Their diameters are between 7 and 14 microns. The sizes of small, non-aggregating grains are mostly between 0. However, their crystalline nature can be observed, but is less visible than for the sample in Fig.
Moreover, in the SEM images Fig. It should be noted that due to inhomogeneous morphology of the investigated samples, the EDX analysis of Nd atoms used at a low content, provides very local information.
Moreover, the EDX measurement of elements present at very low concentrations is charged with a relatively large uncertainty. The theoretically calculated content of Nd and Bi atoms, relative to all atoms in the structure unit of Bi 3 TeBO 9 three Bi atoms, one Te atom, one B atom and nine O atoms and the experimentally measured content of Nd atoms on the basis of EDX data for the series of investigated samples are given in Table 4.
As seen from Table 4 , the Nd content in the studied samples increases with increasing concentration from 0. The same Nd content observed for experimental value for 7. BTBO crystalizes in hexagonal structure with P 6 3 space group. The primitive unit cell of BTBO crystal comprises two formula units and contains 28 atoms engaged in 84 fundamental vibrations.
The modes of B symmetry are inactive both in the Raman and IR spectra [ 13 , 29 , 30 ]. The spectroscopic parameters of all Raman-active bands were analyzed by the fitting procedure using the Lorentzian-like function. The detailed assignment of all Raman-active bands and their determined wavenumbers values are presented in Table S1. As follows from Fig. Many bands in this spectral range have the mixed character.
However, the difference in the transitions intensity observed in the UV excitation and reflectance spectra is a result of different sensitivities of the detectors in the used equipment.
In the visible and UV range, the changes are less pronounced. The shape of these bands is a result of the Stark effect, which describes the shifting and splitting of spectral lines of active ions due to the presence of an external electric crystal field.
The phenomena in which one photon of high energy can convert energy into two photons of lower energy is known as the quantum cutting process [ 36 , 37 ].
After the excitation in VIS at Moreover, the highest intensity NIR emission was observed for 0. The determined lifetimes monitored for the emission at nm under the excitation at and For the other samples 1. In the IH model, the kinetics of the fluorescence intensity was described by the following equation:. Moreover, the energy transfer parameter Q can be determined from the fitting procedure using the following formula:.
Their phase uniformity hexagonal structure of P 6 3 space group was confirmed by XRD. Fthenakis, InTech: Rijeka. Sol Phys — Article Google Scholar. Sci Jung S, Gong D, Yi J The effects of the band gap and defects in silicon nitride on the carrier lifetime and the transmittance in c-Si solar cells.
0コメント